HR: 1340h
AN: A13E-1612    [Abstracts]
TI: Synoptic Analysis of the Pacific-North American Teleconnection Pattern
AU: * Franzke, C
EM: chan1@bas.ac.uk
AF: British Antarctic Survey, High CRoss, Madingley Road, Cambridge, CB3 0ET, United Kingdom
AU: Feldstein, S B
EM: sbf@essc.psu.edu
AF: Earth and Environment Systems Institute The Pennsylvania State University, 2217 Earth-Engineering Science Building, University Park, PA 16802, United States
AU: Lee, S
EM: sl@meteo.psu.edu
AF: Department of Meteorology The Pennsylvania State University, 524 Walker Building, University Park, PA 16802, United States
AB: In this study we investigate the synoptic characteristics of Pacific North America (PNA) teleconnection pattern events by examining the evolution of the potential temperature field on the nominal tropopause (the 2 Potential Vorticity Unit (PVU) surface). This quantity is obtained from the National Center for Environment Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data set. These data cover the period 1958 through 1997 for the months December through February. In this study we present observational evidence that both PNA phases undergo cyclonic wave breaking over the Pacific. The remnants undergo further linear growth and develop into the PNA pattern. The streamfunction anomalies resulting from the cyclonic wave breakings resemble the optimal structures of the PNA, suggesting that the optimal arises from wave breaking. An investigation of the Pacific jet suggests that the phase of the PNA is determined by the strength of the Pacific subtropical jet and is consistent with the theory of stationary waves. A stronger (weaker) jet leads to the positive (negative) phase of the PNA. An investigation of OLR suggests that tropical convection influences the strength of the jet. This is in contrast to the North Atlantic Oscillation (NAO).
DE: 3319 General circulation (1223)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting